Strand treatment



C. A. MGCLURE STRAND TREATMENT Filed NOV. 29, 1967 July 29, 1969 CHARLES A. McCLURE United States Patent O 3,457,613 STRAND TREATMENT Charles A. McClure, R.D. 2, Malvern, Pa. 19355 Continuation-impart of application Ser. No. 543,957, Apr. 20, 1966. This application Nov. 29, 1967, Ser. No. 686,424

Int. Cl. D02g 1/16 U.S. Cl. 28-72.1 10 Claims ABSTRACT F THE DISCLOSURE This invention relates to treatment of textile strands, concerning especially strand drawing and crimping. A process is provided for directing hot uid obliquely onto one side of a textile strand, the opposite side of which is maintained relatively cool. The strand so treated is drawn to increased length and subsequently assumes a crimped configuration upon being forwarded away from the treating location.

This application is a continuation-in-part of my copending patent application, Ser. No. 543,957 tiled Apr. 20, 1966, now U.S. Patent 3,374,514, granted Mar. 26, 1968.

In addition to edge-crimping, gear-crimping, jet-crimping, stutter-crimping, and twist-crimping it is known to crimp textile strands of at least partially oriented (molecularly) linear polymeric material by setting up a temperature gradient transversely of the strand, whereupon the strand assumes a helically crimped configuration under low (or no) tension after cooling of the heated side. In the last mentioned method the heating of the one side of the strand may be accomplished by contact with a hot solid, liquid, or gas; the opposite side is maintained cool -by conductive contact with a solid surface at appropriate temperature. Resulting processing and product characteristics leave a good deal to .be desired, however.

A primary object of the present invention is improved transverse temperature-gradient treatment of ltextile strands.

A further object is continuous drawing and crimping of textile strands.

Another object is provision of improved helical crimp in textile strands.

A still further object is provision of apparatus for accomplishing the foregoing objects.

Other objects of this invention, together with means and methods for attaining the various objects, will be apparent from the following description and the accompanying diagrams.

FIG. 1 is a side elevation, partially schematic, of apparatus according to the present invention; and

FIG. 2 is a side elevation, on an enlarged scale, of a detailed portion of FIG. 1.

FIGURE 3 is a front elevation of a roll component of the preceding views; and

FIG. 4 is oblique sectional view `taken at IV-IV on FIG. 2.

In general, the objects of the present invention are accomplished in treatment of a textile strand wherein the strand is heated on one side and maintained relatively cool on the opposite side, by subjecting the strand on that rst side during the heating thereof to a stream of hot uid incident onto the strand and forwarding the strand in the running direction at a rate greater than the supply rate `of the strand and thereby drawing and crimping the strand continuously.

More particularly the invention comprehends a strandcrimping process comprising supplying a plasticizable molecularly oriented textile strand of linear polymeric material to a treating zone at a rst rate, passing the strand Patented July 29, 1969 through the zone at a second rate greater than the first, heating the strand in the treating zone on one side only to its plasticization temperature by directing thereonto a stream of hot fluid, maintaining the opposite side of the strand cooler than the plasticization temperature, and cooling the strand substantially tension-free, whereupon it assumes a drawn length and a crimped conguration.

FIG. 1 show, in side elevation and partly schematically, strand 10 being withdrawn from supply package 11 yby by the nip of pair of supply rolls 13, 14 from which it passes to and through the nip of roll 12 and anged cool roll 15 rotated at a sufficiently greater surface speed than the supply rolls to draw the strand to increased length by exceeding the elastic limit (usually reached in the vicinity of 10% elongation) but without breaking the strand, the increase in length usually being limited to several times the supply length, although with some undrawn strand compositions a draw of 6 or even higher may be feasible. A draw of about 4X is customary with nylon 6 and 66. The strand takes approximately a half turn about the flanged cool roll, to the recessed peripheral surface of which is juxtaposed jet end 21 of pipe 22 for hot fluid supplied from source 24 through valve 23 in the pipe. From the cool rolls the strand is withdrawn and is forwarded, preferably at reduced rate, about part of roll 17, which is driven or not driven as desired, then past heater 13, and is traversed onto windup package 20 driven by surface contact with traversing drive roll 19. The cool roll rotates on axle 16 (shown sectioned).

FIG. 2 shows, also in side elevation but partly in section and considerably enlarged, a portion of cool roll 15 and adjacent elements. Part of near flange 25 of the roll is broken away, revealing the otherwise concealed corresponding portion of opposite flange 25 as well as jet end 21 and the adjacent length increment of strand 1G. The roll has hollow 23 inside, which is supplied conventionally with cooling fluid (not shown). Jet end 21 is concave in the plane of the view, in juxtaposition to the recessed arcuate peripheral surface of the roll, which suiicient clearance for strand 10 to pass therebetween. The jet outlet is aligned with bore 27 in pipe 22, and the emitted hot uid (not shown) is incident at an oblique angle onto the exposed side of the strand, which runs about the roll in essentially non-slipping contact with that recessed peripheral surface thereof. The supply pressure of the hot uid preferably is such that the velocity component thereof in the direction of strand travel exceeds the rate of travel of the strand.

FIG. 3 shows, in front elevation :on the same scale as in FIG. 2, a portion of cool roll 15, Without strand 10 on recessed peripheral surface 26 thereof, which is anked by a pair of flanges 25, 25'. This view is what would be seen upon looking leftward from a position to the right of cool roll 15 in the preceding views before the strand is strung thereon.

FIG. 4 shows, also in front elevation and partly in section, the elements visible looking obliquely leftward at IV-IV in FIG. 2. Iet end 21 with outlet opening 29 therein is visible end-on, with part of pipe 22, and flanked by part of fianges 25, 25' (shown sectioned) of cool roll 15, which is not otherwise visible. Arrows from the outlet opening denote the ow of hot iluid therefrom which is predominantly upward in this View, corresponding to movement in the running direction of the strand rather than otherwise. The roll anges serve to channel the flow parallel to that direction instead of permitting it to be dissipated in any great part by a transverse velocity cornponent.

The temperature of the hot liuid should be suiciently above the plasticization temperature of the strand cornposition to soften the exposed side of the strand in the relatively brief time it is exposed thereto. For nylon the uid temperature preferably is at least about a couple hundred degrees centigrade. The cool roll should be maintained well below the strand composition plasticization temperature, preferably not more than about twice room temperature in degrees centigrade. The cool side of the strand passes in essentially non-slipping contact with the peripheral surface of the cool roll.

As the hot fluid impinges onto the exposed side of the strand, softening thereof occurs, and at least a latent crimp is imparted thereto. The resultant coniguration of the strand after cooling of the temporarily heated side, chiey by conduction while still on the cool roll, is generally helical, giving the strand a bulky or iiuy appearance, especially when composed of quite a few laments. The effect upon a monolilament is similar though perhaps less extreme in overall elfect because of the lack of other contorted filaments in the same strand. More than one strand may be treated side by side on the same roll if desired, especially where the strands are monotilaments or contain few filaments apiece.

Although only imperfectly understood, the resulting helical crimp in the temporarily tensioned strand may be at least partly attributable to a heat-induced molecular disorientation of the exposed side of the strand such as to preclude subsequent recovery thereof from the increased length imparted thereto by the previously applied tension, Whereas the opposite side, which retained its molecular orientation and consequent elasticity, retracts to become relatively shorter. The difference in length along the respective sides forms the strand into helical configuration.

Heat relaxation of the strand after treatment on the cool roll may be performed by exposure of the cooled strand to an intermediate temperature in heater 18, which is heated in any suitable manner, through which it passes at relatively low tension, or may be deferred until later if desired. The heat-relaxed strand exhibits a more tightly coiled helical coniiguration, as may be desirable.

The composition of the hot treating fluid may be selected for reasons of cost, heat-capacity, chemical plasticizing effect upon the strand composition, or other reasons. Gases are preferred because of the tendency of most liquids to wet the cool roll or the strand or both, which usually is undesirable. Hot air is quite useful accordingly, with or without the admixture of steam, for example. Some steam usually is helpful because of having a plasticizing effect, but excessive steam is usually undesirable because of problems arising from condensation of water on the apparatus. Combustion gases may be employed, such as acetylene or hydrogen with air or oxygen. Other examples of suitable hot fluids will occur to persons ordinarily skilled in the art in the light of the present teaching.

=No attempt will be made to list here the considerable variety of strand compositions subject to successful treatment according to the present invention. No reason is known to rule out any plasticizable strand having a generally linear polymeric composition and at least partially molecularly oriented with respect to the strand axis by predrawing or even by orientation during its formation by extrusion, for example. Cross-linked or three-dimensional polymers, whether organic or inorganic also may be suitable. One or more additional rolls may be added, in contact with the cool roll or between it and the nip rolls to preclude slippage for the purpose of ensuring drawing or simply as a precautionary measure. For best results the radius of the cool roll, in centimeters, should not exceed the cube root of the strand denier. Thus for a 1040 d. strand of carpet yarn, the preferred maximum roll diameter is about 20 cm., and for a 15 d. monolament about 5 cm.

Although a preferred embodiment of this invention has been described above and illustrated in conjunction therewith, the above suggested or other modifications therein, as by adding, combining, or subdividing parts or steps, may be made while retaining all or some of the benefits of the invention.

The claimed invention:

1. In treatment of a running textile strand in a treating zone wherein the strand is heated on one side by flow of hot lluid thereonto and is maintained relatively cool on the opposite side by essentially non-slipping contact with a moving cool solid surface, the improvement comprising supplying the strand to the treating zone at a first rate less than the rate of movement of the cool solid surface and thereby drawing the strand to increased length.

2. The process of claim 1 wherein the strand is drawn therein to at least several times its previous length.

3. Strand-drawing process wherein a running textile strand is drawn to increased length and the running strand is heated momentarily on one side by ow of hot fluid thereonto and is maintained relatively cool on its opposite side while at essentially its drawn length.

4. The process of claim 3 wherein the resulting strand is overfed to a windup location.

5. The process of claim 4 wherein the strand is received substantially tension-free at the windup location and is characterized by a helical crimp coniguration.

6. Strand-crimping process comprising supplying a plasticizable molecularly oriented textile strand of linear polymeric material to a treating zone at a first rate, passing the strand through the treating zone at a second rate greater than the irst and thereby drawing the strand to increased length, heating the strand in the treating zone on one side only to its plasticization temperature by directing thereonto a stream of hot fluid, maintaining the opposite side of the strand 1throughout cooler than the plasticization temperature, and cooling the strand, whereupon it assumes a crimped configuration whenever substantially tension-free.

7. The process of claim 6 wherein the crimped strand is subsequently heated substantially uniformly under tension insufticient to straighten out the crimp.

8. The process of claim 6 wherein the hot stream of gas incident on the one side of the strand partially disorients the molecular structure of the strand on that side relative to the opposite side.

9. Draw-crimping process for molecularly orientable textile strands, comprising drawing such a textile strand to increased length and passing it lengthwise through an arcuate path, maintaining the innermost side of the strand at a temperature at which the strand composition is relatively elastic, heating the outermost side of the strand at an intermediate portion of the path to a temperature at which the strand composition is relatively plastic, and releasing the strand from the arcuate path into a generally helical coniiguration.

10. The process of claim 9 wherein the arcuate path approximates a semi-circle.

References Cited UNITED STATES PATENTS 3,113,366 12/ 1963 Taylor. 3,176,373 4/ 1965 Taylor. 3,347,036 10/ 1967 Daniel. 3,374,302 3/ 1968 Stanley.

FOREIGN PATENTS 225,883 12/ 1959 Australia. 907,823 10/ 1962 Great Britain.

LOUIS K. RIMRODT, Primary Examiner 

